Prosthesis Comprising a Three-Dimensional and Openworked Knit

ABSTRACT

The present invention relates to a prosthesis ( 100 ) comprising an openworked three-dimensional knit ( 101 ) comprising a front face and a rear face, each face being formed with one or more laps of yarns defining pores on said face, the front face being bound to the rear face by connecting yarns defining a spacer, characterized in that the connecting yarns are distributed so that they define an entanglement of yarns crossing each other at the spacer, without obstructing the pores of the front and rear faces.

The invention relates to a prosthesis comprising an openworkedthree-dimensional knit, for example useful as a wall reinforcement inparietal and/or visceral surgery.

By three-dimensional knit, in the sense of the present application, ismeant a knit having a front face and a rear face, each face being formedwith one or more laps of yarns, the front face being bound to the rearface through connecting yarns defining a spacer. The presence of thespacer thereby provides some thickness to the knit: suchthree-dimensional knits may be obtained with a knitting machine of thewarp type or two-bed Rachel type.

By openworked knit, in the sense of the present application, is meantthe feature according to which the knit has pores, or further openvoids, cells, holes or orifices, either regularly distributed or not,promoting cell colonization. The pores may appear in any kinds of shapessuch as for example, spheres, channels, hexagonal shapes.

The spacer as defined above may be formed either with certain yarns ofthe lap(s) of one of the two faces, which regularly leave their originalface for producing a stitch on the other face, and then return to theiroriginal lap, or on the contrary with one or more laps of yarns whichare dedicated to the spacer and which run to and fro from one face tothe other of the knit without being significantly involved in producingeach face.

Openworked three-dimensional knits with a spacer connecting the frontface to the rear face of the knit are already known. Thus documentWO99/05990 describes openworked three-dimensional knits, the spacer ofwhich is produced by one or more laps of connecting yarns dedicated tothe formation of said spacer. As indicated in this document, theconnecting yarns extend perpendicularly from one face towards the otherand form transverse channels parallel with each other.

When they are subject to a compressive force, tending to press the frontface of the knit onto its rear face, or tensile force, the knits asdescribed in WO99/05990 may see the spacer<<be laid down>>or “fall”under this stress, so as to reach a position almost parallel to each ofboth faces: such a phenomenon causes sliding of the front facerelatively to the rear face, this may cause a shift of the pores of thefront face relatively to the pores of the rear face. The knit undergoesa<<flattening>>phenomenon and the walls of the pores of one face maymove and obstruct the pores of the other face. The knit then loses itscapability of promoting cell recolonization. Moreover, it is no longerpossible to see in transparence through the knit, which may be adifficulty for the surgeon upon setting into place a reinforcementprosthesis for example made from such a knit.

Thus, it would be desirable to have a prosthesis comprising anopenworked three-dimensional knit, having a spacer capable ofwithstanding compression and tension, in particular with view toavoiding deformation, and in particular with a view to avoidingcollapse, of the knit when the latter is subject to such stresses. Itwould also be desirable to provide such an improved prosthesis withouthaving to add too much of material forming the knit, in a view to limitforeign material intended to be implanted in the body of a patient.

The object of the present invention is to provide a prosthesiscomprising an openworked three-dimensional knit retaining itsthree-dimensional structure even when it is subject to compressiveforces, for example from one face onto the other, or to tensile forces.

The present invention relates to a prosthesis comprising at least oneopenworked three-dimensional knit comprising two opposite faces, forexample a front face and a rear face, each face being formed with one ormore laps of yarns defining pores on said face, one face being bound tothe opposite face by connecting yarns defining a spacer, characterizedin that the connecting yarns are distributed so that they define anentanglement of yarns which cross each other at the spacer, withoutobstructing the pores of the two opposite faces.

Thus, unlike the knits of the prior art, the connecting yarns of theknit of the prosthesis according to the invention do not form parallelchannels with each other and perpendicular to the faces of the knit. Onthe contrary, in the knit of the prosthesis according to the invention,the yarns of the spacer run from one face to the other of the knitobliquely and not in parallel, i.e. these yarns cross each other, givingthe spacer an <<X profile>> (<<X-stitch>>) or <<crossed profile>>. Inthe knit of the prosthesis according to the invention, at least part ofthe connecting yarns forming the spacer cross each other, giving theknit significant stability of its three-dimensional structure, even whenthe knit is subject to compressive forces, tending to press its frontface onto its rear face. Thus, in the knit of the prosthesis accordingto the invention, the spacer does not tend to place itself in a positionparallel to both faces of the knit when the knit is subject tocompressive forces, and the front face does not slide relatively to therear face. With the knit of the prosthesis according to the invention,the front face remains facing the rear face, without any shift, when theknit is subject to compressive forces. Thus, the pores of the front faceand the pores of the rear face, which for example are facing each otherwhen the knit is at rest, remain in the same relative position even whenthe knit is subject to compressive forces. The transparence of the knitof the prosthesis according to the invention may thereby be maintainedin both situations.

Further, the knit of the prosthesis according to the invention retains agood capability for cell recolonization, even under compression or undertension, the pores of the front face not being obstructed by yarnsforming the walls of the pores of the rear face. The knit of theprosthesis according to the invention retains its three-dimensionalstructure even under compression or under tension.

Resistance to suture of the knit of the prosthesis according to theinvention is also excellent.

In one embodiment, one face being formed with r rows and n columns ofstitches, located facing r′ rows and n′ columns of stitches forming theopposite face, with at least one portion of the connecting yarns, ateither regular row number intervals or not, connects a column n_(i) ofone of the two faces to the column (n_(i)′+x), wherein x ranges from 2to 5, of the opposite face, and, at either regular row number intervalsor not, connects a column n_(j) of one of the two faces to the column(n_(j)′−x′) of the opposite face, wherein x′ ranges from 2 to 5.

In one embodiment, the row number intervals are regular. An optimumentanglement of connecting yarns crossing each other is therebyobtained.

In one embodiment, x=x′, for example, x=x′=2. This means that eitherregularly or not, each connecting yarn connects a column n_(i) of one ofthe two faces, not to the column n_(i)′ located facing the column n_(i)on the opposite face, but to the column (n_(i)′+2) of the opposite face,i.e. to a column of the opposite face shifted by two columns in a firstdirection with respect to the column n_(i)′ of the opposite face. Thus,the connecting yarn is not perpendicular to the faces of the knit but isoblique relatively to these faces. Further, either regularly or not,this yarn also connects a column n_(j), which may for example be thecolumn (n_(i)′+2) above or not, of one of the two faces to anothercolumn (n_(i)′−2) of the opposite face, i.e. shifted by two columns inthe direction opposite to the first direction. Thus, on the whole of theknit of the prosthesis according to the invention, connecting yarnsregularly cross each other at the spacer. The three-dimensionalstability of the spacer, and therefore of the knit, is reinforced. Inanother embodiment, x=x′=3. In such a case, each connecting yarn runsback on the opposite face to a column shifted by three columnsrelatively to its original column of the starting face, in one directionand then in the other. In still another embodiment, x=x′=4. In such acase, each connecting yarn runs back onto the opposite face, to a columnshifted by four columns relatively to its original column of thestarting face, in one direction and then in the other.

In another embodiment, x is different from x′. For example, theconnecting yarn is shifted by 2 columns when it connects one of the twofaces to the opposite face in a lateral direction of the knit and isthen shifted by 3 columns when it again connects one of the two faces tothe opposite face, in the opposite lateral direction.

In one embodiment of the invention, the connecting yarns are yarns fromat least one lap among the laps forming both opposite faces. In such anembodiment, the knit of the prosthesis according to the inventionpreferably does not comprise any additional yarn laps for producing thespacer. Thus, this is, for example, one or more of the lap(s) making upthe front face which include(s) at regular intervals, stitches caughtwith the stitches of one or more of the lap(s) of the rear face, inorder to ensure the connection between both faces. With such embodimentsit is possible to limit the amount of yarns present in the knit of theprosthesis according to the invention, while obtaining a spacer having agood resistance to compressive forces. Thus, the pores of the front faceand the pores of the rear face remain in the same relative position evenwhen the knit is subject to compressive forces. The transparence of theknit is maintained even when the knit is subject to compressive forces.In addition, embodiments where the connecting yarns are yarns from atleast one lap among the laps forming both opposite faces allow obtainingan optimal combination between on one hand the three-dimensional porousstructure of the knit, for a good cell colonization, and on the otherhand the thickness of the knit, which must not be too great in order tofacilitate the introduction of the knit in a trocar in case theprosthesis is implanted via a trocar.

In another embodiment, the connecting yarns are yarns from one or morelaps dedicated to the formation of the spacer. With such embodiments itis possible to use different yarns for forming the spacer with respectto the yarns used for forming the front face and/or the rear face, andto thus impart different properties, for example resorption propertiesto the spacer.

Both opposite faces, for example the front face and the rear face andthe spacer of the knit of the prosthesis according to the invention maybe made in any biocompatible, monofilament and/or multi-filament yarneither bioresorbable or not, customarily used in the making ofprosthetic knits.

In embodiments, the connecting yarns define in addition a set ofparallel or oblique yarns not crossing each other and not obstructingthe pores of the two opposite faces. This set of parallel or obliqueyarns not crossing each other and not obstructing the pores of the twoopposite faces form additional connections between the front and therear face which, in particular when such connecting yarns are yarns fromone lap from the laps forming both opposite faces, bring additionalresistance to compressive force to the knitted structure. In particular,the stability of the three-dimensional structure of the knit isincreased, and the knit thus obtained shows a three-dimensionalstructure particularly capable of resisting to flattening and collapsingwhen a compressive force is applied onto the knit.

The present invention further relates to a prosthesis comprising atleast one openworked three-dimensional knit comprising two oppositefaces, for example a front face and a rear face, each face being formedwith one or more laps of yarns defining pores on said face, one facebeing bound to the opposite face by connecting yarns defining a spacer,the connecting yarns being distributed so that they define anentanglement of yarns crossing each other at the spacer, withoutobstructing the pores of the two opposite faces, said knit beingobtainable by knitting on a knitting machine of the warp or Rachel typecomprising two opposite beds, each respectively with m and m′ needles,the needles m of one bed facing the needles m′ of the opposite bed, theconnecting yarns being distributed over at least one guide bar BE1, saidbar BE1 having at least one lateral movement in one direction from oneneedle m_(i) of one of the two beds to a needle (m_(i)′+x) of theopposite bed, wherein x ranges from 2 to 5, and a lateral movement inthe opposite direction from one needle m_(j) of one of the two beds to aneedle (m_(j)′−x′) of the opposite bed, wherein x′ ranges from 2 to 5.

Thus, during the knitting of the knit, a connecting yarn leaves a needlem_(i) of one face in order to connect either regularly or not, not theneedle m_(i)′ of the opposite face, but a needle shifted by 2, 3, 4 or 5needles in a first direction with respect to the needle m_(i)′. Also,either regularly or not, the connecting yarn connects a needle m_(j) ofone face to a needle of the opposite face, shifted by 2, 3, 4 or 5needles in the direction opposite to the first direction relatively tothe needle m_(j)′.

In an embodiment of the prosthesis according to the invention, the knitis formed by knitting threaded yarns, one full stitch, one empty stitch,on four guide bars BAV, BE1, BAR1 and BAR2, the bars BAV and BE1 formingtwo laps of yarns producing the front face, the bars BAR1 and BAR2forming two laps of yarns producing the rear face and the bar BE1forming the spacer. In such embodiments, it is the yarns of the frontface which achieve the connection between both faces and which thereforeform the spacer. Thus, the bar BE1 is involved in both the formation ofa lap of the front face and in the formation of the spacer.

In an embodiment of the prosthesis according to the invention, the knitis formed by knitting threaded yarns, one full stitch, one empty stitch,on four guide bars BAV, BE1, BAR1 and BAR2, the bars BAV and BE1 formingtwo laps of yarns producing the front face, the bars BAR1 and BAR2forming two laps of yarns producing the rear face and the bar BE1forming the spacer, said laps being knitted according to the schemebelow according to the ISO 11676 standard:

BAV:4.3.2.2/1.0.1.1/1.2.1.1/1.0.1.1/1.2.1.1/1.0.1.1/1.2.3.3/4.5.4.4/4.3.4.4/4.5.4.4/4.3.4.4/4.5.4.4//

BE1:1.2.3.3/4.5.1.2/4.3.4.4/4.5.4.4/4.3.4.4/4.5.4.4/4.3.2.2/1.0.4.3/1.2.1.1/1.0.1.1/1.2.1.1/1.0.1.1//

BAR1:4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0/1.1.1.2/3.3.4.5/4.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5//

BAR2:1.1.1.2/3.3.4.5/4.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5/4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0//

In such a method, yarns of the front face are essentially the ones whichachieve the connection between both faces and therefore the spacer.Thus, the bar BE1 is involved in both the formation of a lap of thefront face and in the formation of the spacer.

Alternatively, the knit is formed by knitting threaded yarns, one fullstitch, one empty stitch, on four guide bars BAV, BE1, BAR1 and BAR2,the bars BAV and BE1 forming two laps of yarns producing the front face,the bars BAR1 and BAR2 forming two laps of yarns producing the rear faceand the bar BE1 forming the spacer, said laps being knitted according tothe scheme below according to the ISO 11676 standard:

BAV1:4.3.2.2/1.0.1.1/1.2.1.1/1.0.1.1/1.2.1.1/1.0.1.1/1.2.3.3/4.5.4.4/4.3.4.4/4.5.4.4/4.3.4.4/4.5.4.4//

BE1:1.2.3.3/4.5.2.1/4.3.4.5/4.5.4.4/4.3.4.5/4.5.4.4/4.3.2.2/1.0.3.4/1.2.1.0/1.0.1.1/1.2.1.0/1.0.1.1//

BAR1:4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0/1.1.1.2/3.3.4.5/4.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5//

BAR2:1.1.1.2/3.3.4.5/4.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5/4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0//

In such a method, the bar BE1 is still involved in both the formation ofa lap of the front face and in the formation of the spacer, but itsscheme has been modified so that the connecting yarns define in additiona set of parallel or oblique yarns not crossing each other and notobstructing the pores of the two opposite faces. Such an embodimentbrings additional connections between the front and the rear faces :such additional connections between the front and the rear face, withconnecting yarns which are yarns from a lap of the front face, bringadditional resistance to compressive force to the knitted structure, aswell as an optimum thickness to the three-dimensional structure of theknit.

In another embodiment of the prosthesis according to the invention, theknit is formed by knitting threaded yarns 1 full stitch, 1 empty stitch,on six guide bars BAV1, BAV2, BE1, BE2, BAR1 and BAR2, the bars BAV1 andBAV2 forming two laps of yarns forming the front face, the bars BAR1 andBAR2 forming two laps of yarns producing the rear face and the bars BE1and BE2 forming the spacer, said laps being knitted according to thescheme below according to the ISO 11676 standard:

BAV1: 1.0.1.1/ 1.2.1.1/ 1.0.1.1/ 2.3.2.2/ 2.1.2.2/ 2.3.3.3/4.5.4.4/4.3.4.4/ 4.5.4.4/ 3.2.3.3/ 3.4.3.3/ 3.2.2.2//

BAV2: 4.5.4.4/ 4.3.4.4/ 4.5.4.4/ 3.2.3.3/ 3.4.3.3/ 3.2.2.2/1.0.1.1/1.2.1.1/ 1.0.1.1/ 2.3.2.2/ 2.1.2.2/ 2.3.3.3//

BE1: 1.1.1.0/ 1.0.1.0/ 1.0.1.1/ 1.1.1.0/ 2.3.2.3/ 2.3.2.2/2.2.2.3/2.3.2.3/ 2.3.2.2/ 2.2.2.3/ 1.0.1.0/ 1.0.1.1//

BE2: 2.2.2.3/ 2.3.2.3/ 2.3.2.2/ 2.2.2.3/ 1.0.1.0/ 1.0.1.1/1.1.1.0/1.0.1.0/ 1.0.1.1/ 1.1.1.0/ 2.3.2.3/ 2.3.2.2//

BAR1: 2.2.1.0/ 1.1.1.2/ 1.1.1.0/ 1.1.2.3/ 2.2.2.1/ 2.2.2.3/3.3.4.5/4.4.4.3/ 4.4.4.5/ 4.4.3.2/ 3.3.3.4/ 3.3.3.2//

BAR2: 3.3.4.5/ 4.4.4.3/ 4.4.4.5/ 4.4.3.2/ 3.3.3.4/ 3.3.3.2/2.2.1.0/1.1.1.2/ 1.1.1.0/ 1.1.2.3/ 2.2.2.1/ 2.2.2.3//

In such a method, the spacer is formed by means of two bars BE1 and BE2,the yarns of which are dedicated to the formation of the spacer.

In an embodiment, at least one of the faces of the knit of theprosthesis according to the invention is covered with an anti-adhesioncoating, in particular in order to avoid the formation of undesiredpost-surgical severe fibrous adhesions.

By <<anti-adhesion>> in the sense of the present application, is meant asmooth and non-porous biocompatible material or coating which does notprovide any space for cell recolonization and avoiding that surroundingorgans adhere onto the prosthesis.

The anti-adhesion material or coating may be selected from bioresorbablematerials, non-bioresorbable materials and mixtures thereof.

Non-bioresorbable anti-adhesion materials may be selected frompolytetrafluoroethylene, polysiloxanes, polyurethanes, stainless steels,derivatives of precious metals and their mixtures.

Preferentially, said anti-adhesion material or coating is bioresorbable:bioresorbable materials suitable for said anti-adhesion coating may beselected from collagens, for example oxidized collagen, oxidizedcelluloses, polyacrylates, trimethylene carbonates, caprolactones,dioxanones, glycolic acid, lactic acid, glycolides, lactides,polysaccharides for example chitosans, polyglucuronic acids, hyaluronicacids, dextrans, fucans, polyethylene glycols, glycerol and mixturesthereof.

In an embodiment of the invention, the material forming theanti-adhesion coating is a hydrophilic bioresorbable material,preferably selected from the group formed by collagens, polysaccharidesand mixtures thereof. Among the collagens which may be used according tothe invention, mention may be made of:

-   -   1) collagen, the helical structure of which is at least partly        thermo-denaturated, without any hydrolytic degradation, the        preparation method of which is described in WO99/06080 the        contents of which is incorporated to the present application by        reference,    -   2) native, non-heated, film collagen with or without glycerin,        crosslinked by gamma irradiation or by any other chemical or        physical means,    -   3) and/or mixtures thereof.

Among the polysaccharides which may used as a resorbable hydrophilicmaterial according to the invention, mention may be made of oxidizedcellulose, hyaluronic acid, starch, chitosan, crosslinked dextransand/or mixtures thereof. All these materials are well known to oneskilled in the art. As an oxidized cellulose suitable for the presentinvention, mention may be made of the product sold under the trade nameof <<Interceed® >> by Ethicon. As hyaluronic acid suitable for thepresent invention, mention may be made of the product sold under thetrade name of <<Hyalobarrier®>> by Fidia Advanced Biopolymers, or of theproduct sold under the trade name of <<Seprafilm®>> by Genzyme.

During the implantation of the prosthesis according to the invention,for example as a wall reinforcement during the treatment of a hernia,the anti-adhesion coating provides protection at least during theinitial healing phase to the knit of the prosthesis at the locationwhere this adherent coating is present, i.e. the covered face(s) of theknit is(are) not exposed to inflammatory cells such as granulocytes,monocytes, macrophages or further giant multi-nucleated cells generallyactivated by the surgical gesture. Indeed, at least during the initialhealing phase, the duration of which may vary from about 5 to 10 days,only the anti-adhesion coating is accessible by the different factorssuch as proteins, enzymes, cytokines or cells of the inflammatory line.

In the case when the anti-adhesion coating consists of non-resorbablematerials, it thus protects the knit before and after implantation, overthe whole period of implantation of the prosthesis.

Moreover, by means of the anti-adhesion coating, the surrounding fragiletissues such as hollow viscera are for example in particular protectedfrom the formation of undesired post-surgical severe fibrous adhesions.

In the case when the anti-adhesion material comprises a bioresorbablematerial, it is preferable to select a bioresorbable material which isnot resorbed before several days so that the anti-adhesion coating mayensure its function of protecting the surrounding organs during the daysfollowing the operation, and, until cell rehabilitation of theprosthesis protects these organs in turn.

In an embodiment, the anti-adhesion coating is in the form of abioresorbable textile. For example, the bioresorbable textile comprisesoxidized cellulose. Such a textile is for example described inUS2007/0032805, the contents of which is incorporated into the presentapplication by reference.

In an embodiment, the anti-adhesion coating is in the form of abioresorbable film.

In an embodiment, the anti-adhesion coating is a film of a mixture ofcollagen and glycerol: the preparation of such a film is described inpatents U.S. Pat. No. 6,451,032, U.S. Pat. No. 6,165,488 and U.S. Pat.No. 6,391,939, the contents of which are incorporated into the presentapplication by reference.

In an embodiment, the anti-adhesion coating is a film of a mixture ofcollagen and chitosan. The preparation of such a film is for exampledescribed in document US2010/0016872, the contents of which isincorporated into the present application by reference.

In an embodiment, the anti-adhesion coating is a film of a mixture ofcollagen and of fucan as described in document US-2009-0005867, thecontents of which is incorporated into the present application byreference. In an embodiment, the anti-adhesion coating is a film of apolysaccharide derivative as described in patent U.S. Pat. No.6,264,702, the contents of which is incorporated into the presentapplication by reference.

In an embodiment, the anti-adhesion coating is a film of cellulose asdescribed in document WO2010/052585, the contents of which isincorporated into the present application by reference.

In an embodiment, the prosthesis according to the invention furthercomprises at least one textile layer in addition to said openworkedthree-dimensional knit, said textile layer being attached to one face ofsaid knit. The textile layer may be any mesh, woven fabric, knit,non-woven fabric, made in a biocompatible material, in particular bymeans of biocompatible yarns, such as for example multifilament yarns,monofilament yarns and combinations thereof. Preferably, the textile isopenworked. The textile may be a knit either identical or different fromsaid openworked three-dimensional knit; it may thus be made according tothe same weaves or not, with the same yarns or with different yarns.

Said textile layer may have the same shape as the shape of theopenworked three-dimensional knit or a different shape. The textilelayer may be attached to one face of the openworked three-dimensionalknit in a continuous way or in a discrete way, by any attachment means,such as for example by sewing, by adhesive, by welding or by acombination of these means.

In an embodiment, as the openworked three-dimensional knit is in theform of a continuous part having a periphery, the textile layer has ashape with a periphery substantially identical with that of said part,said knit and said textile layer being attached to each other at theirrespective periphery, said textile layer being provided with a centralaperture.

Preferably, when the prosthesis comprises an anti-adhesion coating asdescribed above and a textile layer as described above, theanti-adhesion coating is present on the face of the knit opposite to theface where the textile layer is attached.

In such an embodiment, the textile layer, because of the presence of itscentral aperture, forms a kind of skirt which may effectively be used bythe surgeon upon implanting the prosthesis, as an attachment means, bysuturing this skirt to the abdominal wall.

The invention will be better understood from the detailed descriptionand the examples which follow, as well as with the figures wherein:

FIG. 1 is a view of the weave of a knit of a prosthesis according to theinvention,

FIG. 2 is a view of the weave of a knit of another embodiment of aprosthesis according to the invention,

FIG. 3 is a scanning electron microscope view of one face of the knitobtained with the weave of FIG. 1,

FIG. 4 is a top view of an embodiment of a prosthesis according to theinvention,

FIG. 5 is a top view of another embodiment of a prosthesis according tothe invention,

FIG. 6 is a view of the weave of a knit of another embodiment of aprosthesis according to the invention,

FIG. 7 is a scanning electron microscope view of one face of the knitobtained with the weave of FIG. 6.

With reference to FIG. 4, a prosthesis 100 according to the invention isillustrated, comprising an openworked three-dimensional knit 101comprising a front face 102 and a rear face (not visible in the figure):this knit 101 may be produced according to Example 1 below or accordingto Example 2 or according to Example 3 below. Thus, each face of theknit 101 is formed with one or more laps of yarns defining pores on saidface, a face being bound to the opposite face by connecting yarnsdefining a spacer, the connecting yarns are distributed so that theydefine an entanglement of yarns which cross each other at the spacer,without obstructing the pores of the two opposite faces.

In the illustrated example, the knit 101 is in the form of a round partand has a circular periphery 101 a. The prosthesis 100 further comprisesa textile layer 103, having a periphery 103 a substantially identicalwith that of the knit 101. The textile layer 103 is attached through itsperiphery 103 a to the periphery 101 a of the knit 101, and it has acentral aperture 104: the textile layer 103 thereby forms a free skirt105. During the implantation of the prosthesis 100 at a defect of theabdominal wall, for example in the treatment of a hernia, the surgeonmay suture this free skirt 105 to the abdominal wall in order toeffectively attach the prosthesis 100.

The prosthesis 100 further comprises an anti-adhesion coating in theform of a film 106 covering the rear face of the knit 101. In theillustrated example, the film 106 slightly juts out from the peripheries(101 a, 103 a) of the knit 101 and of the textile layer 103. Preferably,the film is obtained from a mixture of oxidized collagen and glycerol asdescribed in patents U.S. Pat. No. 6,451,032, U.S. Pat. No. 6,165,488and U.S. Pat. No. 6,391,939.

Such a film 106 prevents the formation of post-surgical fibrousadhesions.

By the properties of the three-dimensional knit as mentioned in Examples1, 2 and 3 below, the prosthesis according to the invention as describedin FIG. 4 has excellent three-dimensional stability and therefore a goodcapability for cell recolonization, even when the prosthesis is subjectto pressure forces tending to press both faces against each other, asthis may be accomplished by abdominal pressure. The prosthesis accordingto the invention also has excellent resistance to suture.

In FIG. 5, for which the references designating the same elements as forFIG. 4 have been retained, is illustrated a prosthesis 100 similar tothe one of FIG. 4, but the openworked three-dimensional knit 101 has theshape of a globally rectangular part.

The present application also describes a method for treating herniaconsisting of providing a prosthesis according to the invention and ofimplanting it at the hernial defect: for example the face of the knitcovered with the anti-adhesion coating is placed facing the abdominalcavity while the non-covered face, either provided or not with anadditional textile layer forming a skirt, is placed facing the abdominalwall, with view to cell recolonization. When the prosthesis comprises askirt as described above, the surgeon may directly attach the skirt ofthe prosthesis to the abdominal wall by means of sutures or clamps.

Example 1

A knit suitable for the prosthesis according to the invention isproduced with 50 decitex multi-filament polyester yarns, number offilaments per yarn:22.

The knit is produced on a two-bed Rachel knitting machine with 6threaded guide bars 1 full stitch, 1 empty stitch, according to thefollowing weave according to the ISO 11676 standard:

BAV1: 1.0.1.1/ 1.2.1.1/ 1.0.1.1/ 2.3.2.2/ 2.1.2.2/ 2.3.3.3/4.5.4.4/4.3.4.4/ 4.5.4.4/ 3.2.3.3/ 3.4.3.3/ 3.2.2.2//

BAV2: 4.5.4.4/ 4.3.4.4/ 4.5.4.4/ 3.2.3.3/ 3.4.3.3/ 3.2.2.2/1.0.1.1/1.2.1.1/ 1.0.1.1/ 2.3.2.2/ 2.1.2.2/ 2.3.3.3//

BE1: 1.1.1.0/ 1.0.1.0/ 1.0.1.1/ 1.1.1.0/ 2.3.2.3/ 2.3.2.2/2.2.2.3/2.3.2.3/ 2.3.2.2/ 2.2.2.3/ 1.0.1.0/ 1.0.1.1//

BE2: 2.2.2.3/ 2.3.2.3/ 2.3.2.2/ 2.2.2.3/ 1.0.1.0/ 1.0.1.1/1.1.1.0/1.0.1.0/ 1.0.1.1/ 1.1.1.0/ 2.3.2.3/ 2.3.2.2//

BAR1: 2.2.1.0/ 1.1.1.2/ 1.1.1.0/ 1.1.2.3/ 2.2.2.1/ 2.2.2.3/3.3.4.5/4.4.4.3/ 4.4.4.5/ 4.4.3.2/ 3.3.3.4/ 3.3.3.2//

BAR2: 3.3.4.5/ 4.4.4.3/ 4.4.4.5/ 4.4.3.2/ 3.3.3.4/ 3.3.3.2/2.2.1.0/1.1.1.2/ 1.1.1.0/ 1.1.2.3/ 2.2.2.1/ 2.2.2.3//

This weave is illustrated in FIG. 1, in which the bars BAV1, BAV2, BE1,BE2, BAR1 and BAR2, are indicated with for each bar the path of a yarn(indicated in solid lines). In this figure, the numbers 1, 2, 3, . . .12 indicate the rows of stitches of the front face; the numbers 1′, 2′,3′, . . . ,12′ indicate the rows of stitches of the rear face. Also inthis figure, a vertical sequence of points represents two columns ofstitches, both front and rear, facing each other. In FIG. 1, the columnsare indicated as n, n′, (n+1), (n′+1), (n+2) and (n′+2).

In the present example the yarns of the BAV1 and BAV2 bars form thefront face, the yarns of the BE1 and BE2 bars form the spacer and theyarns of the BAR1 and BAR2 bars form the rear face. In the presentexample, the connecting yarns are therefore yarns from laps dedicated tothe formation of the spacer, i.e. the laps obtained with the BE1 and BE2bars.

The weave followed for the front face produces a front face comprisingpores. Also, the weave followed for the rear face produces a facecomprising pores. The pores of the front face are substantially facingthe pores of the rear face.

As this appears in FIG. 1, the yarn of the BE1 bar, at the row 4′ and atthe column n′ of the rear face, does not connect column n of the 5^(th)row of the front face, but it connects column (n+2). By doing this, itconnects the rear face to the front face obliquely and notperpendicularly to these faces. Next, this yarn at the row 10′ of therear face, connects column (n′+2) to column n at the 11^(th) row of thefront face. In the present example, x and x′ as defined in the presentapplication are therefore each equal to 2.

The yarn of the BE2 bar is also involved in the formation of the spacer,symmetrically to the yarn of the BE1 bar.

Thus, the spacer obtained is formed with connecting yarns whichregularly cross each other.

The thereby obtained spacer is particularly resistant to compressiveforces tending to press the front face onto the rear face. Subject tosuch forces, the spacer does neither collapse nor lie down therebyretaining its three-dimensional structure to the knit.

The obtained knit has the following properties:

1°) Thickness: 1.7 mm

By its structure, the knit of the present example substantially retainsits height even when it is subject to a compressive force tending topress its front face onto the rear face.

2°) Transparence and size of the pores for both front and rear faces:

-   -   small pores (width x height): 2.0×2.4 mm    -   large pores (width x height): 2.1×2.5 mm

By the structure of the knit of the present example, the pores of thefront face remain facing the pores of the rear face, even when the knitis subject to a compressive force tending to compress its front faceonto its rear face.

FIG. 3 is a view taken with a scanning electron microscope of one faceof the knit of the present example. As this is apparent from this view,the pores of the front face are distinctly seen (the closest to theapparatus taking the photograph) and it is also possible to distinguishin the background the pores of the rear face: the pores of the frontface and those of the rear face are facing each other. Thus, the knithas excellent transparence which allows the surgeon to handle aprosthesis comprising such a knit with facility and to easily positionit, in particular with respect to the surrounding organs. Indeed, theknit of the prosthesis allows the surgeon to have good visibility intransparence of the surrounding organs.

3°) Suture strength, as measured according to the NF S94-8012007standard “Reinforcement implants set into place via a vaginal route foran urge and/or prolapsus urinary incontinence cure for pelvicorgans—pre-clinical tests and clinical tests”—§5.2.3, 5 samples 50×100mm, USP 2/0 suture yarn, crosshead speed: 100 mm/min

-   -   in the warp direction: 30±3 N    -   in the weft direction: 46±2 N

The above test is conducted on a tensile testing machine HounsfieldHSKS-SN 0589.

The knit retains its three-dimensional structure even when it is subjectto compressive forces tending to press its front face onto its rearface.

This knit is useful for manufacturing reinforcement prosthesis forexample for repairing hernias. It is sufficient to cut out the intendedshape, for example a rectangular (see FIG. 5) or circular shape (seeFIG. 4), in the knit of the present example in order to obtain aprosthesis which may be used as a wall reinforcement for treatinghernia. A prosthesis according to the invention may consist of a knitaccording to the present example, alone, cut to the intended shape.Alternatively, the prosthesis may further comprise an anti-adhesioncoating and/or one or more additional textile layers, as described withreference to FIGS. 4 and 5.

Example 2

A knit suitable for the prosthesis according to the invention isproduced with 88 dtex monofilament polyester yarns.

The knit is produced on a two-bed Rachel knitting machine with 4threaded guide bars, 1 full stitch, 1 empty stitch, according to thefollowing weave, according to the ISO 11676 standard:

BAV:4.3.2.2/1.0.1.1/1.2.1.1/1.0.1.1/1.2.1.1/1.0.1.1/1.2.3.3/4.5.4.4/4.3.4.4/4.5.4.4/4.3.4.4/4.5.4.4//

BE1:1.2.3.3/4.5.1.2/4.3.4.4/4.5.4.4/4.3.4.4/4.5.4.4/4.3.2.2/1.0.4.3/1.2.1.1/1.0.1.1/1.2.1.1/1.0.1.1//

BAR1:4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0/1.1.1.2/3.3.4.5/4.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5//

BAR2:1.1.1.2/3.3.4.5/4.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5/4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0

This weave is illustrated in FIG. 2, in which the bars BAV, BE1, BAR1,and BAR2, are indicated with for each bar the path of a yarn (indicatedin solid line). In this figure, the numbers 1, 2, 3, . . . 15 indicatethe rows of the stitches of the front face; the numbers 1′, 2′, 3′, . .. ,14′ indicate the rows of the stitches of the rear face. Also on thisfigure, a vertical sequence of points illustrates two columns ofstitches, both front and rear, facing each other. In FIG. 2, the columnsare indicated as n, n40 , (n+1), (n′+1), (n+2), (n′+2), (n+3), (n′+3),(n+4) and (n′+4).

In the present example, the yarns of the BAV and BE1 bars form the frontface, the yarns of the BAR1 and BAR2 bars form the rear face. In thepresent example, the connecting yarns are therefore yarns from a lap ofthe front face, i.e. the lap obtained with the BE1 bar. Thus, in thepresent example, there are no laps of connecting yarns dedicated to theformation of the spacer.

The weave followed for the front face produces a front face comprisingpores. Also, the weave followed for the rear face produces a facecomprising pores. The pores of the front face are substantially facingthe pores of the rear face.

As this appears in FIG. 2, the yarn forming the spacer is the yarn ofthe BE1 bar which, at row n° 2 and at column (n+4), connects the frontface to row n° 2′ of the rear face and to the column (n′+1) (see thearrow in the figure). By doing this, it rejoins the front face to therear face obliquely and not perpendicularly to these faces: in thisexample, the yarn is shifted by three columns and x′, as defined in thepresent application, is equal to 3. This yarn then connects row 2′,column (n′+1) of the rear face to row 3, column (n+3) of the front face.By doing this it rejoins the rear face to the front face obliquely andnot perpendicularly to these faces: in this example, the yarn is shiftedby two columns and x, as defined in the present application, is equal to2.

Next this yarn connects the 8^(th) row and column n of the front face torow 8′, column (n′+3) of the rear face (see the arrow in the figure). Bydoing this, it rejoins the front face to the rear face obliquely and notperpendicularly to these faces and x is equal to 3. Next, the yarnconnects row 8′, column (n′+3) of the rear face to row 9, column (n+1)of the front face and here, x′ is equal to 2.

Thus, the obtained spacer is formed with connecting yarns whichregularly cross each other thereby generating an optimum entanglement ofyarns not parallel with each other.

The thereby obtained spacer is particularly resistant to compressiveforces tending to press the front face onto the rear face. Subject tosuch forces, the spacer neither collapses nor lies down parallel to thefront and rear faces, thereby retaining its three-dimensional knittedstructure.

This knit is useful for manufacturing reinforcement prosthesis forexample for repairing hernias. It is sufficient to cut out the intendedshape, for example a rectangular (see FIG. 4) or circular shape (seeFIG. 5), in the knit of the present example in order to obtain aprosthesis which may be used as a wall reinforcement for treating ahernia. A prosthesis according to the invention may consist of a knitaccording to the present example, alone, cut out to the intended shape.Alternatively, the prosthesis may further comprise an anti-adhesioncoating and/or one or more additional textile layers, as described withreference to FIGS. 4 and 5.

Example 3

A knit suitable for the prosthesis according to the invention isproduced with 88 dtex monofilament polyester yarns.

The knit is produced on a two-bed Rachel knitting machine with 4threaded guide bars, 1 full stitch, 1 empty stitch, according to thefollowing weave, according to the ISO 11676 standard:

BAV:4.3.2.2/1.0.1.1/1.2.1.1/1 0.1.1/1.2.1.1/1.0.1.1/1.2.3.3/4.5.4.4/4.3.4.4/4.5.4.4/4.3.4.4/4.5.4.4//

BE1:1.2.3.3/4.5.2.1/4.3.4.5/4.5.4.4/4.3.4.5/4.5.4.4/4.3.2.2/1.0.3.4/1.2.1.0/1.0.1.1/1.2.1.0/1.0.1.1//

BAR1:4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0/1.1.1.2/3.3.4.5/4.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5//

BAR2:1.1.1.2/3.3.4.5/4.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5/4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0

This weave is illustrated in FIG. 6, in which the bars BAV, BE1, BAR1,and BAR2, are indicated with for each bar the path of a yarn (indicatedin solid line). In this figure, the numbers 1, 2, 3, . . . 15 indicatethe rows of the stitches of the front face; the numbers 1′, 2′, 3′, . .. , 14′ indicate the rows of the stitches of the rear face. Also on thisfigure, a vertical sequence of points illustrates two columns ofstitches, both front and rear, facing each other. In FIG. 6, the columnsare indicated as n, n′, (n+1), (n′+1), (n+2), (n′+2), (n+3), (n′+3),(n+4) and (n′+4).

In the present example, the yarns of the BAV and BE1 bars form the frontface, the yarns of the BAR1 and BAR2 bars form the rear face. In thepresent example, the connecting yarns are therefore yarns from a lap ofthe front face, i.e. the lap obtained with the BE1 bar. Thus, in thepresent example, there are no laps of connecting yarns dedicated to theformation of the spacer.

The weave followed for the front face produces a front face comprisingpores. Also, the weave followed for the rear face produces a facecomprising pores. The pores of the front face are substantially facingthe pores of the rear face.

As this appears in FIG. 6, the yarn forming the spacer is the yarn ofthe BE1 bar which, at row n° 2 and at column (n+4), connects the frontface to row n° 2′ of the rear face and to the column (n′+1). By doingthis, it rejoins the front face to the rear face obliquely and notperpendicularly to these faces: in this example, the yarn is shifted bythree columns and x′, as defined in the present application, is equal to3. This yarn then connects row 2′, column (n′+1) of the rear face to row3, column (n+3) of the front face. By doing this it rejoins the rearface to the front face obliquely and not perpendicularly to these faces:in this example, the yarn is shifted by two columns and x, as defined inthe present application, is equal to 2.

This yarn also connects the 8^(th) row and column n of the front face torow 8′, column (n′+3) of the rear face. By doing this, it rejoins thefront face to the rear face obliquely and not perpendicularly to thesefaces and x is equal to 3. Next, the yarn connects row 8′, column (n′+3)of the rear face to row 9, column (n+1) of the front face and here, x′is equal to 2.

Thus, the obtained spacer comprises connecting yarns which regularlycross each other thereby generating an optimum entanglement of yarns notparallel with each other.

In addition, in the present example, the yarn of the BE1 bar formsadditional connections between the front face and the rear face, inwhich the connecting yarns do not cross each other : these additionalconnections may be seen on FIG. 6 at rows 3, 5, 9 and 11.

Indeed, at row n° 3 and at column (n+3), the yarn connects the frontface to row n° 3′ of the rear face and to the column (n′+4). By doingthis, it rejoins the front face to the rear face obliquely and notperpendicularly to these faces: in this example, the yarn is shifted byone column. This yarn then connects row 3′, column (n′+4) of the rearface to row 4, column (n+4) of the front face. By doing this it rejoinsthe rear face to the front face perpendicularly to these faces, with noshift of column. The same phenomenon is repeated starting at row 5.

In addition, at row n° 9 and at column (n+1), the yarn connects thefront face to row n° 9′ of the rear face and to the column n′. By doingthis, it rejoins the front face to the rear face obliquely and notperpendicularly to these faces: in this example, the yarn is shifted byone column. This yarn then connects row 9′, column n′ of the rear faceto row 10, column n of the front face. By doing this it rejoins the rearface to the front face perpendicularly to these faces, with no shift ofcolumn. The same phenomenon is repeated starting at row 11.

Such additional connections between the front and the rear face, withconnecting yarns which are yarns from a lap of the front face, bringadditional resistance to compressive force to the knitted structure.

The thereby obtained spacer is particularly resistant to compressiveforces tending to press the front face onto the rear face. Subject tosuch forces, the spacer neither collapses nor lies down parallel to thefront and rear faces, thereby retaining its three-dimensional knittedstructure.

The obtained knit has the following properties:

1°) Thickness: 1.3 mm

By its structure, the knit of the present example substantially retainsits height even when it is subject to a compressive force tending topress its front face onto the rear face.)

2°) Transparence and size of the pores for both front and rear faces:

-   -   pores (width×height): 2.0×3.3 mm

By the structure of the knit of the present example, the pores of thefront face remain facing the pores of the rear face, even when the knitis subject to a compressive force tending to compress its front faceonto its rear face.

FIG. 7 is a view taken with a scanning electron microscope of one faceof the knit of the present example. As this is apparent from this view,the pores of the front face and of the rear face are aligned on eachother so that it is possible to clearly see the background behind theknit through the knit: the pores of the front face and those of the rearface are facing each other. Thus, the knit has excellent transparencewhich allows the surgeon to handle a prosthesis comprising such a knitwith facility and to easily position it, in particular with respect tothe surrounding organs. Indeed, the knit of the prosthesis allows thesurgeon to have good visibility in transparence of the surroundingorgans.)

3°) Suture strength, as measured according to the NF S94-8012007standard “Reinforcement implants set into place via a vaginal route foran urge and/or prolapsus urinary incontinence cure for pelvicorgans—pre-clinical tests and clinical tests”—§5.2.3, 5 samples 50×100mm, USP 2/0 suture yarn, crosshead speed: 100 mm/min

-   -   in the warp direction: 46±3 N    -   in the weft direction: 50±6 N

The above test is conducted on a tensile testing machine HounsfieldH5KS-SN 0589.

The knit retains its three-dimensional structure even when it is subjectto compressive forces tending to press its front face onto its rearface.

This knit is useful for manufacturing reinforcement prosthesis forexample for repairing hernias. It is sufficient to cut out the intendedshape, for example a rectangular (see FIG. 4) or circular shape (seeFIG. 5), in the knit of the present example in order to obtain aprosthesis which may be used as a wall reinforcement for treating ahernia. A prosthesis according to the invention may consist of a knitaccording to the present example, alone, cut out to the intended shape.Alternatively, the prosthesis may further comprise an anti-adhesioncoating and/or one or more additional textile layers, as described withreference to FIGS. 4 and 5.

1-24. (canceled)
 25. A method of forming a three-dimensional prostheticknit comprising knitting threaded yarns on at least four guide bars BAV,BE1, BAR1 and BAR2, the guide bars BAV and BE1 forming two laps of yarnsproducing a front face of the knit, the guide bars BAR1 and BAR2 formingtwo laps of yarns producing a rear face of the knit and the guide barBE1 forming connecting yarns defining a spacer connecting the front faceto the rear face of the knit, said laps being knitted according to ascheme below in accordance with the ISO 11676 standard:BAV:4.3.2.2/1.0.1.1/1.2.1.111.0.1.1/1.2.1.1/1.0.1.1/1.2.3.3/4.5.4.4/4.3.4.414.5.4.4/4.3.4.4/4.5.4.4//BAR1:4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0/1.1.1.2/3.3.4.5/4.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5//BAR2:1.1.1.213.3.4.514.4.4.3/4.4.4.5/4.4.4.3/4.4.4.5/4.4.4.3/2.2.1.0/1.1.1.2/1.1.1.0/1.1.1.2/1.1.1.0//
 26. The method of claim 25, wherein the knitting of guidebar BE1 is according to a scheme below in accordance with the ISO 11676standard:BE1:1.2.3.3/4.5.1.2/4.3.4.4/4.5.4.4/4.3.4.4/4.5.4.4/4.3.2.2/1.0.4.3/1.2.1.1/1.0.1.1/1.2.1.1/1.0.1.1//
 27. The method of claim 25, wherein the knitting of guide barBE1 is according to a scheme below in accordance with the ISO 11676standard:BE1:1.2.3.3/4.5.2.1/4.3.4.5/4.5.4.4/4.3.4.5/4.5.4.4/4.3.2.2/1.0.3.4/1.2.1.0/1.0.1.1/1.2.1.0/1.0.1.1//28. The method of claim 25, wherein the threaded yarns are one fullstitch, one empty stitch.
 29. The method of claim 25, wherein no laps ofthe connecting yarns are dedicated to the formation of the spacer. 30.The method of claim 25, wherein the knit further comprises pores of thefront face and pores of the rear face, wherein the pores of the frontface substantially face the pores of the rear face.
 31. The method ofclaim 25, wherein the connecting yarns regularly cross each otherthereby generating an optimum entanglement of yarns not parallel witheach other, not crossing each other and not obstructing the pores of thetwo opposite faces.
 32. The method of claim 25, further comprisingattaching a textile layer to one face of the knit.
 33. The method ofclaim 32, wherein the textile layer comprises a central aperture. 34.The method of claim 25, further comprising covering at least one face ofthe knit with an anti-adhesion coating.
 35. The method of claim 34,wherein the anti-adhesion coating is in the form of a bioresorbabletextile.
 36. The method of claim 34, wherein the anti-adhesion coatingis in the form of a bioresorbable film.
 37. The method of claim 32,further comprising covering a face of the knit, opposite the faceincluding the textile layer attached thereto, with an anti-adhesioncoating.
 38. A method of forming a three-dimensional prosthetic knitcomprising knitting threaded yarns on at least six guide bars BAV1,BAV2, BE1, BE2, BAR1 and BAR2, the guide bars BAV1 and BAV2 forming twolaps of yarns producing a front face of the knit, the guide bars BAR1and BAR2 forming two laps of yarns producing a rear face of the knit andthe guide bars BE1 and BE12 forming connecting yarns defining a spacerconnecting the front face to the rear face of the knit, said laps beingknitted according to a scheme below in accordance with the ISO 11676standard:BAV1:1.0.1.1/1.2.1.1/1.0.1.1/2.3.2.2/2.1.2.2/2.3.3.3/4.5.4.4/4.3.4.4/4.5.4.4/3.2.3.3/3.4.3.3/3.2.2.2//BAV2:4.5.4.4/4.3.4.4/4.5.4.4/3.2.3.3/3.4.3.3/3.2.2.2/1.0.1.1/1.2.1.1/1.0.1.1/2.3.2.2/2.1.2.2/2.3,3.3//BE1:1.1.1.0/1.0.1.0/1.0.1.1/1.1.1.0/2.3.2.3/2.3.2.2/2.2.2.3/2.3.2.3/2.3.2.2/2.2.2.3/1.0.1.0/1.0.1.1//BE2:2.2.2.3/2.3.2.3/2.3.2.2/2.2.2.3/1.0.1.0/1.0.1.1/1.1.1.0/1.0.1.0/1.0.1.1/1.1.1.0/2.3.2.3/2.3.2.2//BAR1:2.2.1.0/1.1.1.2/1.1.1.0/1.1.2.3/2.2.2.1/2.2.2.3/3.3.4.5/4.4.4.3/4.4.4.5/4.4.3.2/3.3.3.4/3.3.3.2//BAR2:3.3.4.5/4.4.4.3/4.4.4.5/4.4.3.2/3.3.3.4/3.3.3.2/2.2.1.0/1.1.1.2/1.1.1.0/1.1.2.3/2.2.2.1/2.2.2.3//39. The method of claim 38, wherein the threaded yarns are one fullstitch, one empty stitch.
 40. The method of claim 38, wherein the lapsof the connecting yarns are dedicated to the formation of the spacer.41. The method of claim 38, wherein the knit further comprises pores ofthe front face and pores of the rear face, wherein the pores of thefront face substantially face the pores of the rear face.
 42. The methodof claim 38, wherein the connecting yarns regularly cross each otherthereby generating an optimum entanglement of yarns not parallel witheach other, not crossing each other and not obstructing the pores of thetwo opposite faces.
 43. The method of claim 38, further comprisingattaching a textile layer to one face of the knit.
 44. The method ofclaim 43, wherein the textile layer comprises a central aperture. 45.The method of claim 38, further comprising covering at least one face ofthe knit with an anti-adhesion coating.
 46. The method of claim 45,wherein the anti-adhesion coating is in the form of a bioresorbabletextile.
 47. The method of claim 45, wherein the anti-adhesion coatingis in the form of a bioresorbable film.
 48. The method of claim 43,further comprising covering a face of the knit, opposite the faceincluding the textile layer attached thereto, with an anti-adhesioncoating.
 49. A prosthesis comprising at least one open workedthree-dimensional knit comprising two opposite faces, a front face and arear face, each face being formed with one or several laps of yarnsdefining pores on said face, said front face being bound to the oppositerear face by connecting yarns defining a spacer, wherein the connectingyarns run from the front face to the rear face obliquely and define acrisscrossing set of yarns crossing each other at the spacer, withoutobstructing the pores of the two opposite faces.
 50. The prosthesis ofclaim 49, wherein the spacer is configured to prevent the front facefrom sliding relative to the rear force thereby maintaining the pores ofthe first face and the pores of the second face in the same relativeposition under stress.
 51. The prosthesis of claim 49, wherein the knitcomprises a transparency provided by the pores of the first facesubstantially facing the pores of the second face, and the spacer isconfigured to prevent the front face from sliding relative to the rearforce thereby maintaining the transparency of the knit under stress.